There is an urgent need to expand research on autism to include nonverbal children and adults who have not been included in the exponential rise in investigations into the variability of the developmental phenotypes, pathophysiology, or treatment studies conducted over the past two decades. One major barrier to including this portion of the ASD population in research is the limitation in tools available for their assessment. Our current parent grant (R01 DC 10290) focuses on identifying risk markers for ASD in infants, and our work to date has demonstrated some promise in implicit measures of language and social information processing as well as brain activity, as revealed in eye-tracking, event-related potentials (ERP) and electroencephalography (EEG). The overarching goal of the research described here is to address this important problem by developing novel methods for directly assessing nonverbal children with autism with a specific focus on receptive language, social information processing, and severity of impairment. Specifically, we plan to adapt measures that have shown significant promise in our preliminary data for discriminating high risk infants based on two approaches: (a) eye-tracking;(b) EEG/ERP. Furthermore, the proposed research may also provide important clues to the potential mechanisms that may underlie the severity of impairments in these domains in these children. Aim #1: Develop novel methods for assessing receptive language skills in nonverbal children with autism. We plan to investigate the reliability and validity of eye-tracking measures to assess the children's comprehension of words and basic syntax. We will also investigate the reliability and validity of ERP measures to assess the children's lexical and semantic knowledge to explore whether ERP responses provide a valid index of the children's ability to understand spoken language. The measures will be validated against parent/teacher report measures. Aim #2: Develop novel methods for investigating social information processing in nonverbal children with ASD. We plan to investigate quantitative looking time measures using eye-tracking to pictures of people and complex displays, and video. We will also investigate whether atypical ERP responses to faces provide a valid index of social impairment. These measures will be validated with the Autism Diagnostic Observation Scale and Vineland Socialization subscale. Aim #3: Investigate EEG measures as indices of severity of impairment and atypical behaviors. We plan to investigate whether lower gamma band activity provide an index of severity of overall functional impairment, using the Vineland as our validation measure. We will also explore whether atypical patterns of frontal EEG asymmetry provides a neural marker for problem behaviors, as indexed on the Aberrant Behavior Checklist. Together, this research will lay the groundwork for providing novel methods for assessing nonverbal children that could be readily adapted in both research and clinical settings, and may offer initial insights into some of the mechanisms that explain the profound degree of impairment often seen in nonverbal children. PUBLIC HEALTH RELEVANCE: This goal of this project is to develop innovative methods for assessing receptive language skills, social information processing and severity of impairment in nonverbal school-aged children with autism. Specifically, we plan to adapt eye-tracking and ERP measures that are being used in our ongoing research on infants at risk for ASD (R01 DC 10290) for use as measures for this population who, like infants, are not easily assessed with standardized methods and tests. This research may have an important impact of future clinical evaluations of these children and have the potential for use as outcome measures for treatment studies. The findings may also provide clues to the mechanisms that explain why some of these children fail to acquire spoken language skills.